Watery Mouth Disease

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Watery mouth disease (WMD) will be familiar to most sheep farmers, especially those lambing indoors. Seen in new-born lambs, it’s a bacterial condition that causes signs of lethargy, bloating and perfuse salivation. Affected lambs fail to suck, often lie down and can rapidly progress to collapse and death.

The condition is caused by infection with E. coli, a bacteria that can easily build up in soiled lambing pens. It colonises the lamb’s gut and starts producing toxins that lead to the signs seen.

Once affected mortality can be high. Therapy involves keeping the lamb hydrated and the use of antibiotics or drugs to combat the toxaemia. Oral rehydration with an electrolyte solution should involve at least 50ml/kg four times a day even if the lamb is unable or unwilling to suck. Losses can still be expected to be high, so prevention should be a priority in flocks experiencing high levels of WMD.

On many farms, antibiotics have been used to help control the incidence. However this practice in an example of where improved management can help reduce the amount of antibiotics used on farm. This is an important factor as overuse of antibiotics in animals and humans is well established a major health threat and vets and farmers must work together to limit use of these important drugs.

There are many management steps that can be taken to reduce the incidence of WMD without the use of antibiotics.

Pre lambing ewe nutrition.

WMD is more common in twins and triplets and so a focus on ewe nutrition in the run up to lambing can be beneficial. This will help support birth weight and the quality of maternal colostrum is maximised to improved health and strength in the first critical hours of life.


Ensuring each lamb receives the correct amount of good quality maternal colostrum as soon as possible after birth. The immunoglobulin and energy in colostrum are crucial for a lamb to fight infections, and WMD can become established 12 hours post lambing, so any delay can be lethal. A lamb needs at least 210ml/kg of colostrum and a quarter of this should be in the first two hours. If the ewe cannot produce sufficient quality colostrum then supplementation should be considered.

Good hygiene.

Indoor lambing is a risk factor for WMD as the lambing pen is an ideal environment for E. Coli to build up, increasing the challenge to the lamb. Key activities should include:

  • Cleaning and disinfection of lambing pens between lambing.  Viratek P from Nettex is a powerful broad-spectrum disinfectant for livestock housing. It is specifically formulated for disease control
  • Replacing soiled straw with clean bedding between each lambing.
  • Removal and disposal of afterbirths

These simple practices can be time consuming, especially at the peak of a busy lambing period, but it the importance of good hygiene can’t be overstated.

If antibiotics are regularly used as part of a prevention strategy for WMD these should not be discontinued without discussion with your vet. This can provides an opportunity to review farm practices to identify ways to reduce antibiotic use, improve flock health and boost productivity and profits.